Commit | Line | Data |
---|---|---|
852c2936 MD |
1 | /* |
2 | * ring_buffer_backend.c | |
3 | * | |
e92f3e28 | 4 | * Copyright (C) 2005-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
852c2936 | 5 | * |
e92f3e28 MD |
6 | * This library is free software; you can redistribute it and/or |
7 | * modify it under the terms of the GNU Lesser General Public | |
8 | * License as published by the Free Software Foundation; only | |
9 | * version 2.1 of the License. | |
10 | * | |
11 | * This library is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | * Lesser General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU Lesser General Public | |
17 | * License along with this library; if not, write to the Free Software | |
18 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
852c2936 MD |
19 | */ |
20 | ||
5ad63a16 | 21 | #define _GNU_SOURCE |
2657d1ba | 22 | #include <unistd.h> |
14641deb | 23 | #include <urcu/arch.h> |
96e80018 | 24 | #include <limits.h> |
14641deb | 25 | |
4318ae1b | 26 | #include <lttng/ringbuffer-config.h> |
2fed87ae | 27 | #include "vatomic.h" |
4931a13e MD |
28 | #include "backend.h" |
29 | #include "frontend.h" | |
a6352fd4 | 30 | #include "smp.h" |
431d5cf0 | 31 | #include "shm.h" |
852c2936 MD |
32 | |
33 | /** | |
34 | * lib_ring_buffer_backend_allocate - allocate a channel buffer | |
35 | * @config: ring buffer instance configuration | |
36 | * @buf: the buffer struct | |
37 | * @size: total size of the buffer | |
38 | * @num_subbuf: number of subbuffers | |
39 | * @extra_reader_sb: need extra subbuffer for reader | |
40 | */ | |
41 | static | |
4cfec15c MD |
42 | int lib_ring_buffer_backend_allocate(const struct lttng_ust_lib_ring_buffer_config *config, |
43 | struct lttng_ust_lib_ring_buffer_backend *bufb, | |
852c2936 | 44 | size_t size, size_t num_subbuf, |
a6352fd4 | 45 | int extra_reader_sb, |
38fae1d3 | 46 | struct lttng_ust_shm_handle *handle, |
1d498196 | 47 | struct shm_object *shmobj) |
852c2936 | 48 | { |
34daae3e | 49 | struct channel_backend *chanb; |
852c2936 MD |
50 | unsigned long subbuf_size, mmap_offset = 0; |
51 | unsigned long num_subbuf_alloc; | |
852c2936 | 52 | unsigned long i; |
2657d1ba | 53 | long page_size; |
852c2936 | 54 | |
34daae3e MD |
55 | chanb = &shmp(handle, bufb->chan)->backend; |
56 | if (!chanb) | |
57 | return -EINVAL; | |
58 | ||
852c2936 MD |
59 | subbuf_size = chanb->subbuf_size; |
60 | num_subbuf_alloc = num_subbuf; | |
61 | ||
a6352fd4 | 62 | if (extra_reader_sb) |
852c2936 | 63 | num_subbuf_alloc++; |
852c2936 | 64 | |
2657d1ba MD |
65 | page_size = sysconf(_SC_PAGE_SIZE); |
66 | if (page_size <= 0) { | |
67 | goto page_size_error; | |
68 | } | |
69 | ||
4cfec15c | 70 | align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer_backend_pages_shmp)); |
1d498196 | 71 | set_shmp(bufb->array, zalloc_shm(shmobj, |
4cfec15c | 72 | sizeof(struct lttng_ust_lib_ring_buffer_backend_pages_shmp) * num_subbuf_alloc)); |
b5a3dfa5 | 73 | if (caa_unlikely(!shmp(handle, bufb->array))) |
852c2936 MD |
74 | goto array_error; |
75 | ||
431d5cf0 MD |
76 | /* |
77 | * This is the largest element (the buffer pages) which needs to | |
2657d1ba | 78 | * be aligned on page size. |
431d5cf0 | 79 | */ |
2657d1ba | 80 | align_shm(shmobj, page_size); |
1d498196 | 81 | set_shmp(bufb->memory_map, zalloc_shm(shmobj, |
a6352fd4 | 82 | subbuf_size * num_subbuf_alloc)); |
b5a3dfa5 | 83 | if (caa_unlikely(!shmp(handle, bufb->memory_map))) |
a6352fd4 | 84 | goto memory_map_error; |
852c2936 MD |
85 | |
86 | /* Allocate backend pages array elements */ | |
87 | for (i = 0; i < num_subbuf_alloc; i++) { | |
4cfec15c | 88 | align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer_backend_pages)); |
aead2025 | 89 | set_shmp(shmp_index(handle, bufb->array, i)->shmp, |
1d498196 | 90 | zalloc_shm(shmobj, |
4cfec15c | 91 | sizeof(struct lttng_ust_lib_ring_buffer_backend_pages))); |
4746ae29 | 92 | if (!shmp(handle, shmp_index(handle, bufb->array, i)->shmp)) |
852c2936 MD |
93 | goto free_array; |
94 | } | |
95 | ||
96 | /* Allocate write-side subbuffer table */ | |
4cfec15c | 97 | align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer_backend_subbuffer)); |
1d498196 | 98 | set_shmp(bufb->buf_wsb, zalloc_shm(shmobj, |
4cfec15c | 99 | sizeof(struct lttng_ust_lib_ring_buffer_backend_subbuffer) |
1d498196 | 100 | * num_subbuf)); |
b5a3dfa5 | 101 | if (caa_unlikely(!shmp(handle, bufb->buf_wsb))) |
852c2936 MD |
102 | goto free_array; |
103 | ||
34daae3e MD |
104 | for (i = 0; i < num_subbuf; i++) { |
105 | struct lttng_ust_lib_ring_buffer_backend_subbuffer *sb; | |
106 | ||
107 | sb = shmp_index(handle, bufb->buf_wsb, i); | |
108 | if (!sb) | |
109 | goto free_array; | |
110 | sb->id = subbuffer_id(config, 0, 1, i); | |
111 | } | |
852c2936 MD |
112 | |
113 | /* Assign read-side subbuffer table */ | |
114 | if (extra_reader_sb) | |
115 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, | |
116 | num_subbuf_alloc - 1); | |
117 | else | |
118 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, 0); | |
119 | ||
1ff31389 JD |
120 | /* Allocate subbuffer packet counter table */ |
121 | align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer_backend_subbuffer)); | |
122 | set_shmp(bufb->buf_cnt, zalloc_shm(shmobj, | |
123 | sizeof(struct lttng_ust_lib_ring_buffer_backend_counts) | |
124 | * num_subbuf)); | |
125 | if (caa_unlikely(!shmp(handle, bufb->buf_cnt))) | |
126 | goto free_wsb; | |
127 | ||
852c2936 MD |
128 | /* Assign pages to page index */ |
129 | for (i = 0; i < num_subbuf_alloc; i++) { | |
34daae3e MD |
130 | struct lttng_ust_lib_ring_buffer_backend_pages_shmp *sbp; |
131 | struct lttng_ust_lib_ring_buffer_backend_pages *pages; | |
1d498196 MD |
132 | struct shm_ref ref; |
133 | ||
134 | ref.index = bufb->memory_map._ref.index; | |
135 | ref.offset = bufb->memory_map._ref.offset; | |
136 | ref.offset += i * subbuf_size; | |
137 | ||
34daae3e MD |
138 | sbp = shmp_index(handle, bufb->array, i); |
139 | if (!sbp) | |
140 | goto free_array; | |
141 | pages = shmp(handle, sbp->shmp); | |
142 | if (!pages) | |
143 | goto free_array; | |
144 | set_shmp(pages->p, ref); | |
852c2936 | 145 | if (config->output == RING_BUFFER_MMAP) { |
34daae3e | 146 | pages->mmap_offset = mmap_offset; |
852c2936 MD |
147 | mmap_offset += subbuf_size; |
148 | } | |
149 | } | |
852c2936 MD |
150 | return 0; |
151 | ||
1ff31389 JD |
152 | free_wsb: |
153 | /* bufb->buf_wsb will be freed by shm teardown */ | |
852c2936 | 154 | free_array: |
a6352fd4 MD |
155 | /* bufb->array[i] will be freed by shm teardown */ |
156 | memory_map_error: | |
157 | /* bufb->array will be freed by shm teardown */ | |
852c2936 | 158 | array_error: |
2657d1ba | 159 | page_size_error: |
852c2936 MD |
160 | return -ENOMEM; |
161 | } | |
162 | ||
4cfec15c | 163 | int lib_ring_buffer_backend_create(struct lttng_ust_lib_ring_buffer_backend *bufb, |
a6352fd4 | 164 | struct channel_backend *chanb, int cpu, |
38fae1d3 | 165 | struct lttng_ust_shm_handle *handle, |
1d498196 | 166 | struct shm_object *shmobj) |
852c2936 | 167 | { |
4cfec15c | 168 | const struct lttng_ust_lib_ring_buffer_config *config = &chanb->config; |
852c2936 | 169 | |
1d498196 | 170 | set_shmp(bufb->chan, handle->chan._ref); |
852c2936 MD |
171 | bufb->cpu = cpu; |
172 | ||
173 | return lib_ring_buffer_backend_allocate(config, bufb, chanb->buf_size, | |
174 | chanb->num_subbuf, | |
a6352fd4 | 175 | chanb->extra_reader_sb, |
1d498196 | 176 | handle, shmobj); |
852c2936 MD |
177 | } |
178 | ||
4cfec15c | 179 | void lib_ring_buffer_backend_reset(struct lttng_ust_lib_ring_buffer_backend *bufb, |
38fae1d3 | 180 | struct lttng_ust_shm_handle *handle) |
852c2936 | 181 | { |
34daae3e MD |
182 | struct channel_backend *chanb; |
183 | const struct lttng_ust_lib_ring_buffer_config *config; | |
852c2936 MD |
184 | unsigned long num_subbuf_alloc; |
185 | unsigned int i; | |
186 | ||
34daae3e MD |
187 | chanb = &shmp(handle, bufb->chan)->backend; |
188 | if (!chanb) | |
189 | abort(); | |
190 | config = &chanb->config; | |
191 | ||
852c2936 MD |
192 | num_subbuf_alloc = chanb->num_subbuf; |
193 | if (chanb->extra_reader_sb) | |
194 | num_subbuf_alloc++; | |
195 | ||
34daae3e MD |
196 | for (i = 0; i < chanb->num_subbuf; i++) { |
197 | struct lttng_ust_lib_ring_buffer_backend_subbuffer *sb; | |
198 | ||
199 | sb = shmp_index(handle, bufb->buf_wsb, i); | |
200 | if (!sb) | |
201 | abort(); | |
202 | sb->id = subbuffer_id(config, 0, 1, i); | |
203 | } | |
852c2936 MD |
204 | if (chanb->extra_reader_sb) |
205 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, | |
206 | num_subbuf_alloc - 1); | |
207 | else | |
208 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, 0); | |
209 | ||
210 | for (i = 0; i < num_subbuf_alloc; i++) { | |
34daae3e MD |
211 | struct lttng_ust_lib_ring_buffer_backend_pages_shmp *sbp; |
212 | struct lttng_ust_lib_ring_buffer_backend_pages *pages; | |
213 | ||
214 | sbp = shmp_index(handle, bufb->array, i); | |
215 | if (!sbp) | |
216 | abort(); | |
217 | pages = shmp(handle, sbp->shmp); | |
218 | if (!pages) | |
219 | abort(); | |
852c2936 | 220 | /* Don't reset mmap_offset */ |
34daae3e MD |
221 | v_set(config, &pages->records_commit, 0); |
222 | v_set(config, &pages->records_unread, 0); | |
223 | pages->data_size = 0; | |
852c2936 MD |
224 | /* Don't reset backend page and virt addresses */ |
225 | } | |
226 | /* Don't reset num_pages_per_subbuf, cpu, allocated */ | |
227 | v_set(config, &bufb->records_read, 0); | |
228 | } | |
229 | ||
230 | /* | |
231 | * The frontend is responsible for also calling ring_buffer_backend_reset for | |
232 | * each buffer when calling channel_backend_reset. | |
233 | */ | |
234 | void channel_backend_reset(struct channel_backend *chanb) | |
235 | { | |
14641deb | 236 | struct channel *chan = caa_container_of(chanb, struct channel, backend); |
4cfec15c | 237 | const struct lttng_ust_lib_ring_buffer_config *config = &chanb->config; |
852c2936 MD |
238 | |
239 | /* | |
240 | * Don't reset buf_size, subbuf_size, subbuf_size_order, | |
241 | * num_subbuf_order, buf_size_order, extra_reader_sb, num_subbuf, | |
242 | * priv, notifiers, config, cpumask and name. | |
243 | */ | |
244 | chanb->start_tsc = config->cb.ring_buffer_clock_read(chan); | |
245 | } | |
246 | ||
852c2936 MD |
247 | /** |
248 | * channel_backend_init - initialize a channel backend | |
249 | * @chanb: channel backend | |
250 | * @name: channel name | |
251 | * @config: client ring buffer configuration | |
852c2936 | 252 | * @parent: dentry of parent directory, %NULL for root directory |
2657d1ba | 253 | * @subbuf_size: size of sub-buffers (> page size, power of 2) |
852c2936 | 254 | * @num_subbuf: number of sub-buffers (power of 2) |
38fae1d3 | 255 | * @lttng_ust_shm_handle: shared memory handle |
5ea386c3 | 256 | * @stream_fds: stream file descriptors. |
852c2936 MD |
257 | * |
258 | * Returns channel pointer if successful, %NULL otherwise. | |
259 | * | |
260 | * Creates per-cpu channel buffers using the sizes and attributes | |
261 | * specified. The created channel buffer files will be named | |
262 | * name_0...name_N-1. File permissions will be %S_IRUSR. | |
263 | * | |
264 | * Called with CPU hotplug disabled. | |
265 | */ | |
266 | int channel_backend_init(struct channel_backend *chanb, | |
267 | const char *name, | |
4cfec15c | 268 | const struct lttng_ust_lib_ring_buffer_config *config, |
a3f61e7f | 269 | size_t subbuf_size, size_t num_subbuf, |
a9ff648c | 270 | struct lttng_ust_shm_handle *handle, |
5ea386c3 | 271 | const int *stream_fds) |
852c2936 | 272 | { |
14641deb | 273 | struct channel *chan = caa_container_of(chanb, struct channel, backend); |
852c2936 MD |
274 | unsigned int i; |
275 | int ret; | |
6c1f7d8b | 276 | size_t shmsize = 0, num_subbuf_alloc; |
2657d1ba | 277 | long page_size; |
852c2936 MD |
278 | |
279 | if (!name) | |
280 | return -EPERM; | |
281 | ||
2657d1ba MD |
282 | page_size = sysconf(_SC_PAGE_SIZE); |
283 | if (page_size <= 0) { | |
284 | return -ENOMEM; | |
285 | } | |
852c2936 | 286 | /* Check that the subbuffer size is larger than a page. */ |
2657d1ba | 287 | if (subbuf_size < page_size) |
852c2936 MD |
288 | return -EINVAL; |
289 | ||
290 | /* | |
12bcbbdb MD |
291 | * Make sure the number of subbuffers and subbuffer size are |
292 | * power of 2, and nonzero. | |
852c2936 | 293 | */ |
12bcbbdb | 294 | if (!subbuf_size || (subbuf_size & (subbuf_size - 1))) |
e52b0723 | 295 | return -EINVAL; |
12bcbbdb | 296 | if (!num_subbuf || (num_subbuf & (num_subbuf - 1))) |
e52b0723 | 297 | return -EINVAL; |
3d8e9399 MD |
298 | /* |
299 | * Overwrite mode buffers require at least 2 subbuffers per | |
300 | * buffer. | |
301 | */ | |
302 | if (config->mode == RING_BUFFER_OVERWRITE && num_subbuf < 2) | |
303 | return -EINVAL; | |
852c2936 MD |
304 | |
305 | ret = subbuffer_id_check_index(config, num_subbuf); | |
306 | if (ret) | |
307 | return ret; | |
308 | ||
852c2936 MD |
309 | chanb->buf_size = num_subbuf * subbuf_size; |
310 | chanb->subbuf_size = subbuf_size; | |
311 | chanb->buf_size_order = get_count_order(chanb->buf_size); | |
312 | chanb->subbuf_size_order = get_count_order(subbuf_size); | |
313 | chanb->num_subbuf_order = get_count_order(num_subbuf); | |
314 | chanb->extra_reader_sb = | |
315 | (config->mode == RING_BUFFER_OVERWRITE) ? 1 : 0; | |
316 | chanb->num_subbuf = num_subbuf; | |
a6352fd4 MD |
317 | strncpy(chanb->name, name, NAME_MAX); |
318 | chanb->name[NAME_MAX - 1] = '\0'; | |
193183fb | 319 | memcpy(&chanb->config, config, sizeof(*config)); |
852c2936 | 320 | |
1d498196 | 321 | /* Per-cpu buffer size: control (prior to backend) */ |
4cfec15c MD |
322 | shmsize = offset_align(shmsize, __alignof__(struct lttng_ust_lib_ring_buffer)); |
323 | shmsize += sizeof(struct lttng_ust_lib_ring_buffer); | |
1d498196 MD |
324 | |
325 | /* Per-cpu buffer size: backend */ | |
326 | /* num_subbuf + 1 is the worse case */ | |
327 | num_subbuf_alloc = num_subbuf + 1; | |
4cfec15c MD |
328 | shmsize += offset_align(shmsize, __alignof__(struct lttng_ust_lib_ring_buffer_backend_pages_shmp)); |
329 | shmsize += sizeof(struct lttng_ust_lib_ring_buffer_backend_pages_shmp) * num_subbuf_alloc; | |
2657d1ba | 330 | shmsize += offset_align(shmsize, page_size); |
1d498196 | 331 | shmsize += subbuf_size * num_subbuf_alloc; |
4cfec15c MD |
332 | shmsize += offset_align(shmsize, __alignof__(struct lttng_ust_lib_ring_buffer_backend_pages)); |
333 | shmsize += sizeof(struct lttng_ust_lib_ring_buffer_backend_pages) * num_subbuf_alloc; | |
334 | shmsize += offset_align(shmsize, __alignof__(struct lttng_ust_lib_ring_buffer_backend_subbuffer)); | |
335 | shmsize += sizeof(struct lttng_ust_lib_ring_buffer_backend_subbuffer) * num_subbuf; | |
1d498196 MD |
336 | /* Per-cpu buffer size: control (after backend) */ |
337 | shmsize += offset_align(shmsize, __alignof__(struct commit_counters_hot)); | |
338 | shmsize += sizeof(struct commit_counters_hot) * num_subbuf; | |
339 | shmsize += offset_align(shmsize, __alignof__(struct commit_counters_cold)); | |
340 | shmsize += sizeof(struct commit_counters_cold) * num_subbuf; | |
341 | ||
852c2936 | 342 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { |
4cfec15c | 343 | struct lttng_ust_lib_ring_buffer *buf; |
852c2936 | 344 | /* |
a6352fd4 | 345 | * We need to allocate for all possible cpus. |
852c2936 | 346 | */ |
852c2936 | 347 | for_each_possible_cpu(i) { |
1d498196 | 348 | struct shm_object *shmobj; |
5ea386c3 | 349 | |
74d81a6c | 350 | shmobj = shm_object_table_alloc(handle->table, shmsize, |
5ea386c3 | 351 | SHM_OBJECT_SHM, stream_fds[i]); |
afdf9825 MD |
352 | if (!shmobj) |
353 | goto end; | |
4cfec15c MD |
354 | align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer)); |
355 | set_shmp(chanb->buf[i].shmp, zalloc_shm(shmobj, sizeof(struct lttng_ust_lib_ring_buffer))); | |
1d498196 MD |
356 | buf = shmp(handle, chanb->buf[i].shmp); |
357 | if (!buf) | |
358 | goto end; | |
5d61a504 | 359 | set_shmp(buf->self, chanb->buf[i].shmp._ref); |
1d498196 MD |
360 | ret = lib_ring_buffer_create(buf, chanb, i, |
361 | handle, shmobj); | |
852c2936 MD |
362 | if (ret) |
363 | goto free_bufs; /* cpu hotplug locked */ | |
364 | } | |
852c2936 | 365 | } else { |
1d498196 | 366 | struct shm_object *shmobj; |
4cfec15c | 367 | struct lttng_ust_lib_ring_buffer *buf; |
a6352fd4 | 368 | |
74d81a6c | 369 | shmobj = shm_object_table_alloc(handle->table, shmsize, |
5ea386c3 | 370 | SHM_OBJECT_SHM, stream_fds[0]); |
afdf9825 MD |
371 | if (!shmobj) |
372 | goto end; | |
4cfec15c MD |
373 | align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer)); |
374 | set_shmp(chanb->buf[0].shmp, zalloc_shm(shmobj, sizeof(struct lttng_ust_lib_ring_buffer))); | |
1d498196 | 375 | buf = shmp(handle, chanb->buf[0].shmp); |
a6352fd4 MD |
376 | if (!buf) |
377 | goto end; | |
cb14bae9 | 378 | set_shmp(buf->self, chanb->buf[0].shmp._ref); |
1d498196 MD |
379 | ret = lib_ring_buffer_create(buf, chanb, -1, |
380 | handle, shmobj); | |
852c2936 MD |
381 | if (ret) |
382 | goto free_bufs; | |
383 | } | |
384 | chanb->start_tsc = config->cb.ring_buffer_clock_read(chan); | |
385 | ||
386 | return 0; | |
387 | ||
388 | free_bufs: | |
a6352fd4 MD |
389 | /* We only free the buffer data upon shm teardown */ |
390 | end: | |
852c2936 MD |
391 | return -ENOMEM; |
392 | } | |
393 | ||
852c2936 MD |
394 | /** |
395 | * channel_backend_free - destroy the channel | |
396 | * @chan: the channel | |
397 | * | |
398 | * Destroy all channel buffers and frees the channel. | |
399 | */ | |
1d498196 | 400 | void channel_backend_free(struct channel_backend *chanb, |
38fae1d3 | 401 | struct lttng_ust_shm_handle *handle) |
852c2936 | 402 | { |
45e9e699 | 403 | /* SHM teardown takes care of everything */ |
852c2936 MD |
404 | } |
405 | ||
852c2936 MD |
406 | /** |
407 | * lib_ring_buffer_read - read data from ring_buffer_buffer. | |
408 | * @bufb : buffer backend | |
409 | * @offset : offset within the buffer | |
410 | * @dest : destination address | |
411 | * @len : length to copy to destination | |
412 | * | |
413 | * Should be protected by get_subbuf/put_subbuf. | |
414 | * Returns the length copied. | |
415 | */ | |
4cfec15c | 416 | size_t lib_ring_buffer_read(struct lttng_ust_lib_ring_buffer_backend *bufb, size_t offset, |
38fae1d3 | 417 | void *dest, size_t len, struct lttng_ust_shm_handle *handle) |
852c2936 | 418 | { |
34daae3e MD |
419 | struct channel_backend *chanb; |
420 | const struct lttng_ust_lib_ring_buffer_config *config; | |
a6352fd4 | 421 | ssize_t orig_len; |
4cfec15c | 422 | struct lttng_ust_lib_ring_buffer_backend_pages_shmp *rpages; |
852c2936 | 423 | unsigned long sb_bindex, id; |
99b99b47 | 424 | void *src; |
852c2936 | 425 | |
34daae3e MD |
426 | chanb = &shmp(handle, bufb->chan)->backend; |
427 | if (!chanb) | |
428 | return 0; | |
429 | config = &chanb->config; | |
852c2936 MD |
430 | orig_len = len; |
431 | offset &= chanb->buf_size - 1; | |
a6352fd4 | 432 | |
b5a3dfa5 | 433 | if (caa_unlikely(!len)) |
852c2936 | 434 | return 0; |
a6352fd4 MD |
435 | id = bufb->buf_rsb.id; |
436 | sb_bindex = subbuffer_id_get_index(config, id); | |
4746ae29 | 437 | rpages = shmp_index(handle, bufb->array, sb_bindex); |
a6352fd4 MD |
438 | /* |
439 | * Underlying layer should never ask for reads across | |
440 | * subbuffers. | |
441 | */ | |
442 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
443 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
444 | && subbuffer_id_is_noref(config, id)); | |
99b99b47 MD |
445 | src = shmp_index(handle, shmp(handle, rpages->shmp)->p, |
446 | offset & (chanb->subbuf_size - 1)); | |
447 | if (caa_unlikely(!src)) | |
448 | return 0; | |
449 | memcpy(dest, src, len); | |
852c2936 MD |
450 | return orig_len; |
451 | } | |
852c2936 | 452 | |
852c2936 MD |
453 | /** |
454 | * lib_ring_buffer_read_cstr - read a C-style string from ring_buffer. | |
455 | * @bufb : buffer backend | |
456 | * @offset : offset within the buffer | |
457 | * @dest : destination address | |
458 | * @len : destination's length | |
459 | * | |
0bf3c920 | 460 | * Return string's length, or -EINVAL on error. |
852c2936 | 461 | * Should be protected by get_subbuf/put_subbuf. |
0bf3c920 | 462 | * Destination length should be at least 1 to hold '\0'. |
852c2936 | 463 | */ |
4cfec15c | 464 | int lib_ring_buffer_read_cstr(struct lttng_ust_lib_ring_buffer_backend *bufb, size_t offset, |
38fae1d3 | 465 | void *dest, size_t len, struct lttng_ust_shm_handle *handle) |
852c2936 | 466 | { |
34daae3e MD |
467 | struct channel_backend *chanb; |
468 | const struct lttng_ust_lib_ring_buffer_config *config; | |
a6352fd4 | 469 | ssize_t string_len, orig_offset; |
852c2936 | 470 | char *str; |
4cfec15c | 471 | struct lttng_ust_lib_ring_buffer_backend_pages_shmp *rpages; |
852c2936 MD |
472 | unsigned long sb_bindex, id; |
473 | ||
34daae3e MD |
474 | chanb = &shmp(handle, bufb->chan)->backend; |
475 | if (!chanb) | |
476 | return -EINVAL; | |
477 | config = &chanb->config; | |
0bf3c920 MD |
478 | if (caa_unlikely(!len)) |
479 | return -EINVAL; | |
852c2936 | 480 | offset &= chanb->buf_size - 1; |
852c2936 | 481 | orig_offset = offset; |
852c2936 MD |
482 | id = bufb->buf_rsb.id; |
483 | sb_bindex = subbuffer_id_get_index(config, id); | |
4746ae29 | 484 | rpages = shmp_index(handle, bufb->array, sb_bindex); |
a6352fd4 MD |
485 | /* |
486 | * Underlying layer should never ask for reads across | |
487 | * subbuffers. | |
488 | */ | |
489 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
852c2936 MD |
490 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE |
491 | && subbuffer_id_is_noref(config, id)); | |
aead2025 | 492 | str = shmp_index(handle, shmp(handle, rpages->shmp)->p, offset & (chanb->subbuf_size - 1)); |
99b99b47 MD |
493 | if (caa_unlikely(!str)) |
494 | return -EINVAL; | |
a6352fd4 MD |
495 | string_len = strnlen(str, len); |
496 | if (dest && len) { | |
497 | memcpy(dest, str, string_len); | |
498 | ((char *)dest)[0] = 0; | |
499 | } | |
500 | return offset - orig_offset; | |
852c2936 | 501 | } |
852c2936 MD |
502 | |
503 | /** | |
504 | * lib_ring_buffer_read_offset_address - get address of a buffer location | |
505 | * @bufb : buffer backend | |
506 | * @offset : offset within the buffer. | |
507 | * | |
508 | * Return the address where a given offset is located (for read). | |
509 | * Should be used to get the current subbuffer header pointer. Given we know | |
22b22ce9 MD |
510 | * it's never on a page boundary, it's safe to read/write directly |
511 | * from/to this address, as long as the read/write is never bigger than | |
512 | * a page size. | |
852c2936 | 513 | */ |
4cfec15c | 514 | void *lib_ring_buffer_read_offset_address(struct lttng_ust_lib_ring_buffer_backend *bufb, |
1d498196 | 515 | size_t offset, |
38fae1d3 | 516 | struct lttng_ust_shm_handle *handle) |
852c2936 | 517 | { |
4cfec15c | 518 | struct lttng_ust_lib_ring_buffer_backend_pages_shmp *rpages; |
34daae3e MD |
519 | struct channel_backend *chanb; |
520 | const struct lttng_ust_lib_ring_buffer_config *config; | |
852c2936 MD |
521 | unsigned long sb_bindex, id; |
522 | ||
34daae3e MD |
523 | chanb = &shmp(handle, bufb->chan)->backend; |
524 | if (!chanb) | |
525 | return NULL; | |
526 | config = &chanb->config; | |
852c2936 | 527 | offset &= chanb->buf_size - 1; |
852c2936 MD |
528 | id = bufb->buf_rsb.id; |
529 | sb_bindex = subbuffer_id_get_index(config, id); | |
4746ae29 | 530 | rpages = shmp_index(handle, bufb->array, sb_bindex); |
852c2936 MD |
531 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE |
532 | && subbuffer_id_is_noref(config, id)); | |
aead2025 | 533 | return shmp_index(handle, shmp(handle, rpages->shmp)->p, offset & (chanb->subbuf_size - 1)); |
852c2936 | 534 | } |
852c2936 MD |
535 | |
536 | /** | |
537 | * lib_ring_buffer_offset_address - get address of a location within the buffer | |
538 | * @bufb : buffer backend | |
539 | * @offset : offset within the buffer. | |
540 | * | |
541 | * Return the address where a given offset is located. | |
542 | * Should be used to get the current subbuffer header pointer. Given we know | |
543 | * it's always at the beginning of a page, it's safe to write directly to this | |
544 | * address, as long as the write is never bigger than a page size. | |
545 | */ | |
4cfec15c | 546 | void *lib_ring_buffer_offset_address(struct lttng_ust_lib_ring_buffer_backend *bufb, |
1d498196 | 547 | size_t offset, |
38fae1d3 | 548 | struct lttng_ust_shm_handle *handle) |
852c2936 | 549 | { |
a6352fd4 | 550 | size_t sbidx; |
4cfec15c | 551 | struct lttng_ust_lib_ring_buffer_backend_pages_shmp *rpages; |
34daae3e MD |
552 | struct channel_backend *chanb; |
553 | const struct lttng_ust_lib_ring_buffer_config *config; | |
852c2936 | 554 | unsigned long sb_bindex, id; |
34daae3e | 555 | struct lttng_ust_lib_ring_buffer_backend_subbuffer *sb; |
852c2936 | 556 | |
34daae3e MD |
557 | chanb = &shmp(handle, bufb->chan)->backend; |
558 | if (!chanb) | |
559 | return NULL; | |
560 | config = &chanb->config; | |
852c2936 MD |
561 | offset &= chanb->buf_size - 1; |
562 | sbidx = offset >> chanb->subbuf_size_order; | |
34daae3e MD |
563 | sb = shmp_index(handle, bufb->buf_wsb, sbidx); |
564 | if (!sb) | |
565 | return NULL; | |
566 | id = sb->id; | |
852c2936 | 567 | sb_bindex = subbuffer_id_get_index(config, id); |
4746ae29 | 568 | rpages = shmp_index(handle, bufb->array, sb_bindex); |
852c2936 MD |
569 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE |
570 | && subbuffer_id_is_noref(config, id)); | |
aead2025 | 571 | return shmp_index(handle, shmp(handle, rpages->shmp)->p, offset & (chanb->subbuf_size - 1)); |
852c2936 | 572 | } |